DAY 2 CONVECTIVE OUTLOOK
VALID 06Z TUE 01/04 - 06Z WED 02/04 2003
ISSUED: 31/03 22:57Z
FORECASTER: DAHL

GENERAL THUNDERSTORMS ARE FORECAST ACROSS SOUTHERN EUROPE.

GENERAL THUNDERSTORMS ARE FORECAST ACROSS NORTHWESTERN AND CENTRAL EUROPE.

SYNOPSIS

IMPRESSIVE UPPER TROUGH ATTM WEST OF THE BRITISH ISLES ... WILL RAPIDLY DIG SOUTHEAST AND REACH THE NORTHERN MEDITERRANEAN SEA TOWARDS THE END OF THIS PERIOD. IN ITS WAKE ... MASSIVE UPPER RIDGE IS PROGGED TO BUILD ACROSS THE NORTHERN ATLANTIC OCEAN. AHEAD OF THE TROUGH ... SURGE OF SUBSTROPICAL AIRMASS IS EXPECTED TO SPREAD ACROSS CENTRAL EUROPE ON TUESDAY.

DISCUSSION

...CENTRAL AND NORTHWESTERN EUROPE...
PROBLEM APPEARS TO BE THE SHORT RESIDENCE TIME OF THE SUBTROPICAL AIRMASS OVER THE EUROPEAN CONTINENT ... LIMITING MODIFICATION OF THIS AIRMASS SO AS TO YIELD SOME CAPE. ALSO ... INSOLATION SHOULD BE OBSTRUCTED BY OPAQUE CLOUDINESS/RAIN IN THE NARROW WARM SECTOR. PRIND THAT PRECIP WILL BE LARGELY STRATIFORM ... WITH A NARROW LINE OF SHALLOW STRONLY FORCED CONVECTION ALONG THE SURFACE COLD FRONT. THOUGH LIGHTNING STRIKES SHOULD BE VERY ISOLATED /IF ANY OCCURS AT ALL/ CONVECTION WILL LIKELY AUGMENT STRONG SURFACE WINDS ... AND MARGINALLY SEVERE GUSTS MAY OCCUR. IF WARM-SECTOR AIRMASS TURNED OUT TO BE LATENT UNSTABLE IN A DEEPER LAYER THAN CURRENTLY EXPECTED ... THREAT OF ORGANIZED SEVERE THUNDERSTORMS WOULD EXIST AND AN UPGRADE TO SLIGHT WOULD WOULD BE NECESSARY WITH TOMORROW'S OUTLOOK.

LESS CONDITIONAL CONVECTIVE SCENARIO WILL EXIST IN THE POSTFRONTAL ENVIRONMENT WITHIN DEEP POLAR AIMASS. FIELD OF ENHANCED CUMULUS CLOUDS WILL LIKELY DEVELOP BENEATH CVA MAX ... WHICH IS EXPECTED TO REACH THE SOUTHEASTERN NORTH SEA ON WEDNESDAY MORNING. MODELS AGREE IN WEAKNING THE WIND FIELD TOWARDS WEDNESDAY MORNING SO THAT THE THREAT OF SEVERE THUNDERSTORMS SHOULD DIMINISH BEFORE THE SYSTEM MAKES LANDFALL. HOWEVER ... EARLIER ON TUESDAY ... A FEW CONVECTIVELY-ENHANCED SEVERE WIND GUSTS ALONG WITH SMALL HAIL WILL BE POSSIBLE OVER GREAT BRITAIN. ALSO ... A FEW LOW-TOP SUPERCELLS CANNOT BE RULED OUT ... AND THE CHANCE OF AN ISOLATED TORNADO OR TWO WILL BE SOMEWHAT ENHANCED.

...SOUTHERN EUROPE...
AIRMASS OVER THE SOUTHERN PARTS OF EUROPE SHOULD BECOME MARGINALLY UNSTABLE WITH DAYTIME HEATING. GFS AND GME INDICATE BANDS OF 500 HPA CVA STRETCHING INTO NORTHERN ITALY AND THE IBERIAN PENINSULA LATE IN THE DAY WHICH WILL LIKELY PROMOTE TSTM DEVELOPMENT. ADDITIONAL THUNDERSTORMS SHOULD FORM OVER ITALY ... ALONG THE COLD FRONT OVER THE SOUTHERN BALKAN STATES AND OVER SOUTH IBERIA BENEATH WEAK DCVA REGIME. ALTHOUGH SMALL HAIL AND GUSTY WINDS ARE POSSIBLE WITH ANY OF THE STORMS ... CHANCE OF ORGANIZED SEVERE IS TOO LOW FOR A SLGT RISK ATTM.

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